What is the total number of atoms?

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

a) adding base pairs

c) unwinding the helix

there are possible two correct answers for this question.

dna polymerase doesn’t add base pairs, it adds single nucleotides which are complentar to coding strand . also dna polymerase can’t unwind the dna helix alone. dna helicase can do that, using energy derived from atp hydrolysis.

dna polymerase are enzymes that synthesize dna molecules from deoxyribonucleotides. these enzymes replicate the dna strand and create two identical dna strands from a single original dna molecule. some of dna polymerases have a function of correcting erros which are made during replication and this process is called proofreading. if the dna polymerase detects that incorrectly paired nucleotide has been added, it will remove and replace the wrong nucleotide.